6991394686 has 16 divisors (see below), whose sum is σ = 11022938784. Its totient is φ = 3319300864.

The previous prime is 6991394633. The next prime is 6991394719. The reversal of 6991394686 is 6864931996.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 548395 + ... + 560998.

It is an arithmetic number, because the mean of its divisors is an integer number (688933674).

Almost surely, 2^6991394686 is an apocalyptic number.

6991394686 is a deficient number, since it is larger than the sum of its proper divisors (4031544098).

6991394686 is a wasteful number, since it uses less digits than its factorization.

6991394686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1109555.

The product of its digits is 15116544, while the sum is 61.

The square root of 6991394686 is about 83614.5602511907. The cubic root of 6991394686 is about 1912.1469864110.

The spelling of 6991394686 in words is "six billion, nine hundred ninety-one million, three hundred ninety-four thousand, six hundred eighty-six".